North Korea’s trade dependence on China deepened over the past four years, in contrast to a reduction in South Korea’s share in the North’s external trade, Seoul’s Unification Ministry said in a report Sunday.

The proportion of China in North Korea’s foreign trade is on the rise, increasing from 41.6 percent in 2007 to 49.5 percent in 2008, 52.7 percent in 2009 and 57.1 percent last year, the report said.

By contrast, South Korea saw its share of the North’s trade declining from 38.0 percent in 2007 to 33.0 percent in 2009 to 31.4 percent last year, it noted.

In terms of trade volume, too, bilateral trade between North Korea and China jumped from US$1.97 billion in 2007 to $2.68 billion in 2009 and $3.47 billion in 2010, the report said, adding the inter-Korean trade volume slightly increased from $1.8 billion in 2007 to $1.91 billion last year.

As this information was released in South Korea, the DPRK’s premier, Choe Yong-rim, is in China. According to the Korea Times:

The North’s Premier Choe Yong-rim and his Chinese counterpart Wen Jiabao “pledged to promote trade, investment and economic cooperation” between the nations during a meeting held on Monday night during Choe’s official visit to China, Xinhua news agency said.

“Under the context of the complicated regional and international situation, the parties, governments and peoples of China and the DPRK (North Korea)…made joint efforts to push forward bilateral ties,” Xinhua quoted Wen as telling Choe during the talks.

Wen hailed the North’s achievements in developing its economy and vowed that Beijing will continue to offer assistance within its capability, according to the report.

He then called on the two sides to speed up mutually beneficial cooperation in fields such as trade, investment, infrastructure, natural resources and agriculture, the report said.

South Korea’s perceived failure to compete with China for economic influence in the North as a result of heightened tensions in inter-Korean relations remains an active subject of frustration in South Korea, especially among progressives, but North Korea’s continued pursuit of nuclear and missile tests and other tension-raising provocations against the South make it clear that China has been unable to use the North’s economic dependency on Beijing as a tool for imposing political restraint on Pyongyang.